This is a note to let you know that I've just added the patch titled
ext4: avoid overlapping preallocations due to overflow
to the 6.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-avoid-overlapping-preallocations-due-to-overflo.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0452d65101de63b63569eeb8aed51334fb5c4008
Author: Baokun Li <libaokun1@xxxxxxxxxx>
Date: Mon Jul 24 20:10:59 2023 +0800
ext4: avoid overlapping preallocations due to overflow
[ Upstream commit bedc5d34632c21b5adb8ca7143d4c1f794507e4c ]
Let's say we want to allocate 2 blocks starting from 4294966386, after
predicting the file size, start is aligned to 4294965248, len is changed
to 2048, then end = start + size = 0x100000000. Since end is of
type ext4_lblk_t, i.e. uint, end is truncated to 0.
This causes (pa->pa_lstart >= end) to always hold when checking if the
current extent to be allocated crosses already preallocated blocks, so the
resulting ac_g_ex may cross already preallocated blocks. Hence we convert
the end type to loff_t and use pa_logical_end() to avoid overflow.
Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230724121059.11834-4-libaokun1@xxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 627c813cf0759..5c3055a32e57a 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4223,12 +4223,13 @@ ext4_mb_pa_rb_next_iter(ext4_lblk_t new_start, ext4_lblk_t cur_start, struct rb_
static inline void
ext4_mb_pa_assert_overlap(struct ext4_allocation_context *ac,
- ext4_lblk_t start, ext4_lblk_t end)
+ ext4_lblk_t start, loff_t end)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_prealloc_space *tmp_pa;
- ext4_lblk_t tmp_pa_start, tmp_pa_end;
+ ext4_lblk_t tmp_pa_start;
+ loff_t tmp_pa_end;
struct rb_node *iter;
read_lock(&ei->i_prealloc_lock);
@@ -4237,7 +4238,7 @@ ext4_mb_pa_assert_overlap(struct ext4_allocation_context *ac,
tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
pa_node.inode_node);
tmp_pa_start = tmp_pa->pa_lstart;
- tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len);
+ tmp_pa_end = pa_logical_end(sbi, tmp_pa);
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted == 0)
@@ -4259,14 +4260,14 @@ ext4_mb_pa_assert_overlap(struct ext4_allocation_context *ac,
*/
static inline void
ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac,
- ext4_lblk_t *start, ext4_lblk_t *end)
+ ext4_lblk_t *start, loff_t *end)
{
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_prealloc_space *tmp_pa = NULL, *left_pa = NULL, *right_pa = NULL;
struct rb_node *iter;
- ext4_lblk_t new_start, new_end;
- ext4_lblk_t tmp_pa_start, tmp_pa_end, left_pa_end = -1, right_pa_start = -1;
+ ext4_lblk_t new_start, tmp_pa_start, right_pa_start = -1;
+ loff_t new_end, tmp_pa_end, left_pa_end = -1;
new_start = *start;
new_end = *end;
@@ -4285,7 +4286,7 @@ ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac,
tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
pa_node.inode_node);
tmp_pa_start = tmp_pa->pa_lstart;
- tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len);
+ tmp_pa_end = pa_logical_end(sbi, tmp_pa);
/* PA must not overlap original request */
spin_lock(&tmp_pa->pa_lock);
@@ -4365,8 +4366,7 @@ ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac,
}
if (left_pa) {
- left_pa_end =
- left_pa->pa_lstart + EXT4_C2B(sbi, left_pa->pa_len);
+ left_pa_end = pa_logical_end(sbi, left_pa);
BUG_ON(left_pa_end > ac->ac_o_ex.fe_logical);
}
@@ -4405,8 +4405,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_super_block *es = sbi->s_es;
int bsbits, max;
- ext4_lblk_t end;
- loff_t size, start_off;
+ loff_t size, start_off, end;
loff_t orig_size __maybe_unused;
ext4_lblk_t start;
